A survey that challenged IT managers to imagine the data center of 2025 offers up some optimistic, even surprising, findings.

About 800 IT data center managers globally responded to the Emerson Network Power survey and three of its major findings foretell major changes ahead:

First, by 2025, data center managers expect nearly 25% of their power will come from solar energy, which today accounts for about 1% of a data center's energy supply.

Second, in 10 years, nearly three-quarters of the respondents believe that at least 60% of computing will be cloud based.

And third, 58% of managers expect data centers will smaller in 10 years: 30% predicted they'll be one-half the size of today's data center, 18%, one-fifth the size, and 10%, one-tenth the size.

The renewable energy finding may be the survey's most striking. Today, solar, wind, fuel cells, geothermal and tidal energy sources account for no more than 10% of a data center's power. But in 10 years, these renewables will account for 50% of a data center's power, with fuel cells accounting for about 11% of that 50% figure.

That confidence in renewable energy may be optimistic, and indicates that managers "are imaging some fairly large technical breakthroughs that are going to happen in the renewable space," said Steve Hassell, president of data center solutions for Emerson Network Power.

Currently, a square meter solar panel can generate 800 kWh per year. Supporting power densities of 6.4 kWh, which is near the average for a rack, requires eight square meters of solar panels -- more when cooling is considered. But the use of solar is increasing. Apple, for instance, has a 100-acre solar array to help power its data center in Maiden, N.C.

The current trend in rack densities is holding at 6-to-8 kWh, said Hassell, although there are data centers with racks that that use as much as 40 kWh.

"We haven't seen a dramatic increase in rack density," said Hassell. But the survey respondents expect that will change, with 26% predicting power densities of 80 kWh in 10 years, and another 15% who envision 100 kWh densities.

The survey also picked up a shift in private power generation, especially in regions of the world where the grid is less reliable.

Apple's private power generation efforts, illustrated by its solar farm, may become more common in the data center industry, at least among large "hyperscale" providers. Google's decision to locate a data center near a hydroelectric dam in Washington State might fall under the private power generation definition as well, said Hassell.

Those surveyed also had a lot of confidence in a self-healing, full visibility, self-optimizing data center, which may arrive with the increasing adoption of software-defined data centers and data center infrastructure management.

The respondents were broken out by region, and among those from the U.S., half expect to still be in the data center business by 2025, with 37% saying they will be retired by that point. In the Asia Pacific region, only 10% of the respondents said they would be retired in 10 years.